A comparative study and optimization of corrosion resistance of ZnAl layered double hydroxides films intercalated with different anions on AZ31 Mg alloys

The inhibitory and comparative effects of Zn-Al layered double hydroxide microcontainers intercalated with benzotriazole and nitrite for corrosion protection coatings on AISI 1010 carbon steel

“…These initial results may be correlated with the epoxy resin adherence within the substrate. For the samples that contain only epoxy resin, there was no pore formation but in the system with LDH, therefore, the formation of pores was observed in the coating with LDH-NO 2 and with particle agglomerations of the coating with LDH-BTA -/ NO 2 that created superficial pores, as shown in Figure 3A,B and C. The pore occurrence, as suggested by Tang et al [26], may contribute to surface electrolyte permeation affecting the initial OCP results ( Figure 4B). However, after filling the pores with electrolyte, the coating that contains LDH-NO 2 blocked the aggressive ion permeation.…”

Effects of Al3+ concentration in hydrothermal solution on the microstructural and corrosion resistance properties of fabricated MgO ceramic layer on AZ31 magnesium alloy

“…Generally, with higher R ct values, the corrosion resistance is improved. [ 41 ] According to the fitting results (Table 2), the HT/MAO coating possessed an apparently higher R ct than the bare AZ31 alloy and MAO coatings, implying that coating compactness is of crucial importance in providing corrosion resistance. [ 5 ] Furthermore, the R coat of the HT/MAO coating increased from 2.75 × 10 5 to 2.99 × 10 6 Ω·cm 2 as Al 3+ concentration increased from 0 (HT‐0/MAO) to 0.05 mol/L (HT‐0.05/MAO), a substantial increment over the MAO ceramic layer (4.67 × 10 4 Ω·cm 2 ).…”

Reconstruction of the ZnAl Mixed Oxides Into the Layered Double Hydroxide Catalysts Active in the Aldol Condensation of Furfural: The Role of ZnO Particles

“…We focused on ZnAl-reconstructed LDHs (RE-LDHs). In general, ZnM LDHs (M Al 3+ , Fe 3+ , Ga 3+ , and Ti 3+ ) (Palmer et al, 2011;Wang and Zhang, 2012;Kikhtyanin et al, 2018;Bukhtiyarova, 2019;Santamaría et al, 2020;Szabados et al, 2020) can be prepared by several methods from various precursors of given metals, such as nitrates (Bellezza et al, 2014;Zeng et al, 2017;Tang et al, 2019), chlorides (Ambrogi et al, 2012;Zhang and Li, 2014) or sulfates (Mishra et al, 2017).…”

“…The most widely used method for the preparation of ZnM LDHs is the coprecipitation of the solutions of salts in different Zn/M ion ratios in a basic medium, where the pH of the medium is maintained and the given materials are precipitated during synthesis. The basic buffer can be Na 2 CO 3 (Jiang et al, 2010;Kumar and Pant, 2020), NaOH (Nishimura et al, 2013;Tang et al, 2019), any combination thereof (Smoláková et al, 2011;Zeng et al, 2017;Liu and Yang, 2018;Teodorescu et al, 2020), or other solutions that are not widely used, such as a mixture of either Na 2 CO 3 and (NH 4 ) 2 CO 3 (Korošec et al, 2020) or urea, Na 2 CO 3 , and NaOH (Gil et al, 2020) or aqueous ammonia solution (Bellezza et al, 2014). The quality of the resultant product depends on the pH, which must be maintained during synthesis.…”